Nanodiamonds produced by detonation synthesis using carbon-containing explosives as the precursor material are valuable for diverse applications. While the primary particle size of these detonation nanodiamonds (DND) is 4-5 nm, during processes of synthesis and purification these particles become agglomerated and appear as aggregates when suspended in solvents. For example, DND aggregates in water are typically between 200 and 400 nm. In order to utilize DND for many applications, it is important to isolate smaller particles from larger aggregates. The current methods for size-fractionation of DND have drawbacks including being labor intensive. Some fractionation schemes require surface modification of the DND, which is sometimes undesirable.